This is the Secret of Fire. Create depth with your painting. After painting fire with normal paints, when it is dry, paint it again with clear paints. That will provide a level of depth that ordinary paints can't match. Here I start with Tamiya Clear Red. It goes on just like the solid colors, just paint it on randomly, over the other colors, covering about a third of the surface of the fire.
Next is Tamiya Color, Clear Orange. I paint the clear on from dark to lighter colors for more depth. This covers a third of the surface, just like the Clear Red.
Once all the other paints are dry, paint the whole fire with Tamiya Color Clear. Use at least three coats of clear. It will create a greater depth than the other colors alone.
Here they are, all the colors needed to paint the base and paint fire. Not counting the white primer that I used to start the whole project! I try and paint a lot of fire at one time because it's a lot of different colors to fool with for a small project. Painting fire is easy, but time consuming. Enjoy, and don't burn yourself.